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Abstract
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As part of their immune system plants have pattern recognition receptors (PRRs) that can detect a broad range of microbe-associated molecular patterns (MAMPs). Here, we identified a novel PRR of Arabidopsis thaliana with specificity for the new bacterial MAMP 'emax' from Xanthomonads. Response to emax seems restricted to the Brassicaceae family and also varied among different accessions of A. thaliana. In crosses between sensitive accessions and the insensitive accession Shakhdara emax perception mapped to the receptor–like protein 1 (RLP1). Functional complementation of rlp1 mutants required gene constructs that code for an N-terminally extended version of RLP1 that we termed ReMAX for ‘receptor of emax’. ReMAX is a typical RLP with structural similarity to the tomato RLP Eix2 that detects fungal xylanase as a MAMP. Attempts to demonstrate receptor function by interfamily transfer of ReMAX to Nicotiana benthamiana were successful after using hybrid receptors with the C-terminal part of ReMAX replaced by that of Eix2. These results show that ReMAX determines specificity for emax. They also demonstrate hybrid receptor technology as a promising tool to overcome problems that impede interfamily transfer of PRRs to enhance pathogen detection in crop plants.
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